One of the numerous modern methods of treating Hallus Valgus is chevron osteotomy of the first metatarsal bone. It was introduced by Dale W. Austin in the USA in 1962 and it came to Europe in the 1980s. It got its name from the V-shaped pattern called “chevron”. In medical publications this method of surgical treatment is also called Austin osteotomy after the surgeon who introduced it. The main advantage of osteotomy is easy performance and great long-lasting results.
Chevron osteotomy helps draw the heads of the first and second metatarsal bones together, taking into account dorsoplantar dislocation (angle reduction), restore physiological conditions – eliminate incongruence and subluxation and also medial pseudoexostosis of the head of the first metatarsal bone, achieve free movement in the foot, reconstruct the anatomic proportion in accord with biomechanics and correctithe position of sesamoid bones. It is widely used for correction of first degree Hallux Valgus as this method implies performing a three-to-five-centimeter incision and it is quite effective at correcting deformities. Toe bones are carefully fixed with screws and wires.
- with equal shoulder-length incisions
- with a prolonged dorsal incision
- with a plantar incision
If incisions are of the same length, osteosynthesis is not stable as fixation of the proximal fragment is performed by fixating a screw to the thin part of the cancellous bone of the metaphysis and it can easily get crumpled or fractured by implementation of a screw. Thus, a tissue defect can develop and chevron osteotomy will be useless. If the plantar part of the incision is longer, fixation is much easier and more stable since the screw coming through the cortex of the proximal fragment pulls up the head of the metatarsal bone perfectly well, coming into its cancellous bone.
Various fixators are used for osteosynthesis and fixation of bone fragments: cortical screws with the 3,5-milimeter diameter, needles, in some cases vicryl and wiry cerclages and also intracortical Barouk screws. If necessary, osteotomy of feet is performed along with some additional surgeries.
Nowadays therapy is much more innovated especially concerning the size and direction of bone fragments and also modifications which allow correcting the length of the first metatarsal bone and angulation of the surface of its joint:
Osteotomy must be performed along with correction of soft tissues so that thin bones located on cartilages (sesamoid bones) could get into the correct position easier and faster. During the postoperative period plaster immobilization is not performed usually. It is allowed to wear heels already on the second day after surgery. Patients are sent home on the twelfth day and they are recommended walking with basic load on the heels within next 4 weeks (depending on their weight, age and type of osteoporosis).